2008 Ford F-350 Super Duty XL 4dr SuperCab LB (5.4L 8cyl 6M)
I had a hard time during my 27000 to 28000 km mark. My fuel economy went from 690 km per tank to 390. Wow! It took 3 attempts and two diffrent dealerships to fix. I blew all my o rings and injectors. I was blown away as 1 injector maybe but all of them wow. So after a mechanic it's all back to normal and my economy is still climbing.